Method and apparatus for treatment of contaminated soil particles

Abstract

Soil that is contaminated by hydrocarbons or other deleterious chemicals is processed through a soil shredding apparatus to break the soil into small particles having a substantially uniform maximum size. The particles are then conveyed to a location above a deposit area and directed onto the deposit area to form a growing pile of contaminated particles. Concurrently, a substantially cone shaped spray of an aqueous solution containing anti-contaminating agents, such as bacteriological microbes is sprayed on the pile. The configuration of the conical pile, taken in conjunction with the application of the liquid spray produces a rolling of the particles down the sides of the growing conical pile, thereby insuring the contacting of substantially all of the surfaces of each particle by the liquid containing the decontaminating agents. Concurrently, the moisture content of the conical pile of contaminated particles is periodically checked, and the flow rate of the liquid spray is appropriately adjusted to maintain a desired minimum water content and concentration of anti-contaminating agents within the conical pile of soil particles.

I claim: 
     
       1. The method of treating contaminated soil with a aqueous solution of decontaminating/agents comprising: breaking the contaminated soil into particles of substantially uniform maximum size;   forming a stream of said particles having a selected mass flow rate;   directing said stream of particles downward onto a selected surface in a manner to build a growing cone shaped mass of contaminated soil particles; and   concurrently applying a cone shaped, downwardly discharge of an aqueous solution of decontaminating agents to said growing cone shaped mass at a rate selected to produce moistening of said growing cone shaped mass and assist in rolling of newly deposited particles down the sides of said cone shaped mass to expose more of each particle's surface area to contact by said aqueous solution of decontaminating agents.   
     
     
       2. The method of claim 1 further comprising the step of: continuously measuring the water content of said particles in said cone shaped mass; and   adjusting the flow rate of said downward discharge to maintain a selected minimum water content and a selected concentration of decontaminating agents in said growing cone shaped mass of contaminated soil particles.   
     
     
       3. The method of claim 2 further comprising the step of providing a plurality of adjustable flow rate, downwardly directed, horizontally spaced spray nozzles to apply said downward discharge of the aqueous solution of decontaminating agents; and selectively adjusting the flow rates of said nozzles to maintain said selected minimum water content and concentration of decontaminating agents in said growing cone-shaped mass of contaminated soil particles.   
     
     
       4. The method of claim 3 further comprising the step of providing a computer; measuring moisture content of said growing cone-shaped mass and entering signals in said computer representing said varying moisture content;   weighing the mass flow rate of said stream of particles and entering signals in said computer representing said mass flow rate; and   controlling the mass flow rate of said stream of contaminated particles and the flow rates of said nozzles by said computer to maintain a selected minimum moisture content in said growing cone shaped mass of contaminated particles.   
     
     
       5. The method of claim 4 further comprising the steps of utilizing said computer to indicate total mass of particles treated. 
     
     
       6. The method of claim 4 further comprising the steps of utilizing said computer to indicate total gallonage of decontaminating solution applied. 
     
     
       7. Apparatus for decontaminating soil contaminated by environmentally undesirable chemicals comprising, in combination, means for shredding the contaminated soil into particles of substantially uniform maximum size;   means for conveying the contaminated soil particles at a selected rate to an overhead position relative to a non-contaminated surface;   means for discharging said contaminated soil particles from said overhead position to form a growing cone-shaped mass of contaminated particles on said non-contaminated surface; and   means for concurrently applying a spray of a aqueous solution of decontaminating agents to the external surfaces of said growing cone-shaped mass, thereby assisting in downward rolling movement of particles moistened by said spray to expose more of the surfaces of said contaminated soil particles to contact with said aqueous solution.   
     
     
       8. Apparatus for decontaminating soil contaminated by environmentally undesirable chemicals comprising, in combination, means for shredding the contaminated soil into particles of substantially uniform maximum size;   means for conveying the contaminated soil particles at a selected rate to an overhead position relative to a non-contaminated surface;   means for discharging said contaminated soil particles from said overhead position to form a growing cone-shaped mass of contaminated particles on said non-contaminated surface;   means for concurrently applying a spray of a aqueous solution of decontaminating agents to all surfaces of said growing cone-shaped mass, thereby assisting in downward rolling movement of particles moistened by said spray to expose more of the surfaces of said contaminated soil particles to contact with said aqueous solution;   means for detecting the water content of the contaminated soil particles; and   means for controlling the flow rate of said aqueous solution to maintain a selected minimum moisture content in said growing conical mass of contaminated particles.   
     
     
       9. The apparatus of claim 7 further comprising a computer; means for supplying first input signals to said computer indicating the mass flow delivery rate of said contaminated soil particles to said overhead position;   means for continuously measuring the water content of said growing conical mass of contaminated soil particles and generating second input signals to said computer; and   means controlled by said computer for varying the volume of said spray of liquid solution of decontaminating agents to maintain a selected minimum water content and concentration of decontaminating agents in said conical growing mass of said contaminated particles.   
     
     
       10. The apparatus of claim 9 further comprising means operable by said computer for indicating the total mass of soil particles treated. 
     
     
       11. The apparatus of claim 9 further comprising means operable by said computer for indicating the total gallonage of treatment fluid applied to the contaminated soil particles. 
     
     
       12. The apparatus of claim 7 further comprising means for aerating the interior of said cone shaped pile. 
     
     
       13. The apparatus of claim 8 wherein said means for detecting the moisture content of said contaminated soil particles comprises a vertical center post around which said growing cone-shaped mass of contaminated particles is formed; and a plurality of moisture detectors mounted on said center post in vertically spaced relation.   
     
     
       14. The apparatus of claim 13 wherein said center post is hollow, and further comprising a plurality of pipes secured to said hollow center post in vertically spaced, radially projecting relationship, whereby a fluid may be supplied to the interior of said conical mass through said hollow center post.